Currently, dimethyl sulfoxide is generally produced by the oxidation of dimethyl sulfide. The common production methods are as follows.
1. Methanol-Carbon Disulphide Method: methanol and carbon disulphide are used as starting material with γ-Al2O3 as the catalyst to firstly synthesize dimethyl sulfide. Then the resulting dimethyl sulfide is oxidized with nitrogen dioxide (or nitric acid) to produce dimethyl sulfoxide.2. Nitrogen Dioxide Method: methanol and hydrogen sulfide are used as starting material in the presence of γ-alumina to produce dimethyl sulfide; sulfuric acid and sodium nitrite are reacted to produce nitrogen dioxide; the resulting dimethyl sulfide and nitrogen dioxide are subjected to oxidation at 60-80° C. to produce a crude dimethyl sulfoxide, or the resulting dimethyl sulfide is directly oxidized with oxygen gas to produce a crude dimethyl sulfoxide; and the crude dimethyl sulfoxide is subjected to a vacuum distillation to produce a refined dimethyl sulfoxide.3. Dimethyl Sulfate Method: dimethyl sulfate and sodium sulphide are reacted to produce dimethyl sulfide; sulfuric acid and sodium nitrite are reacted to produce nitrogen dioxide; dimethyl sulfide and nitrogen dioxide are subjected to oxidation to produce a crude dimethyl sulfoxide, which is neutralized and distilled to produce a refined dimethyl sulfoxide.
In addition, dimethyl sulfoxide can also be produced from dimethyl sulfide by the anode oxidation method.